CASE PRESENTATION AND LITERATURE REVIEW OF SQUAMOUS HISTOLOGY IN UTERINE CANCER

Purpose: Although the most common form of endometrial cancer is pure endometrioid adenocarcinoma, there have been many instances of endometrioid adenocarcinoma with squamous differentiation. However, the incidence of pure squamous carcinoma of the endometrium is very rare. Here a case is presented of a woman with endometrial cancer that was found to contain both glandular and squamous components and was described as endometrial adenocarcinoma with extensive squamous morule formation with areas of necrosis. The objective is to compare and contrast endometrioid adenocarcinoma with squamous differentiation (EASD) and primary squamous carcinoma of the endometrium (PSCE). Methods: A current literature review of online research databases and relevant scientific journals was performed in order to compare what is known about the incidence, etiology, histopathology, diagnosis, treatment, and prognosis of PSCE with that of EASD. Results: The origin of the squamous differentiation within endometrioid adenocarcinoma arises from squamous metaplasia of glandular tissue that eventually forms adenocarcinoma. However, the origin of PSCE is postulated to arise from stem cells between glandular basement membrane and endometrial columnar epithelium. While one possible component of treatment for EASD is hormone therapy, PSCE has been shown not to express estrogen or progesterone receptors and thus is not responsive to hormone therapy. The prognosis for pure endometrioid adenocarcinoma at five years for stage I disease is 89.1%; for stage II disease is 78.8%; for stage III disease is 57.8%; and for stage IV disease is 22%. EASD has been shown to have a worse prognosis than pure endometrioid adenocarcinoma. PSCE is much less common and thus only studied out to one year. At one year, the prognosis for stage I disease is 80%; for stage III is 20%; and for stage IV is 0%. Conclusions: While EASD and PSCE share the similarity of squamous features, PSCE carries a much worse prognosis with more limited treatment options. With so few cases and so little known about PSCE, further research on this lethal carcinoma is warranted